Originally Posted by exMaggieDrum
Couple of quick questions:
- where did you buy your cells?
- how did you turn off the alternator
field(s) - at the BMS warning time or the cutout, or??
I live in Germany
, hence I bought them at a local dealer (LiTrade Shop | Akkus und Zubehör für Elektroautos
). I took the cells home and top-balanced them manually.
I ordered the cells "pre-balanced" which means that the vendor connected my cells in parallel and charged them to 3.6 V just prior to shipping
. When they arrived, I temporarily arranged them in their final 4P4S configuration, labeled them so I could reproduce this and discharged the pack a bit (a few percent) using a 4 Ohm 50 W resistor.
I temporarily rigged the BMS and an improvised HVC relay to be safe (and test the BMS). Then I used a lab power supply to bring the pack to 14.4 V (3.6 V cell voltage) again.
I monitored the entire charging
process thoroughly and watched cell voltage closely. The blinking cell module indicators helped identify the "top charged" cells. I then used a 1 Ohm 25 W resistor to bridge the one cell pack that was edging on the top for about 5 - 10 seconds. Repeated this until all cell packs showed the same voltage.
Once the pack was top balanced with this method, I discharged the pack to 60 %, disassembled and stowed them for transport to the boat
. There I reassembled the pack and installed them physically.
The whole process has been described in this thread several times and I just repeated what I learned here. Thanks to all who shared their knowledge!
is a Balmar
6 type with an external Balmar
MC 614 regulator
. The MC 614 provides a "Ignition" input. It only supplies field to the alternator if the "Ignition" input carries +12 V. In my setup this input is wired to the ignition circuit and is disabled by the HVC relay controlled by the BMS.
My setup does not have a "warning only" stage. I rely on my charging
sources being configured correctly, providing 13.8 (14.0 for solar
, they don't have voltage sense) to the batteries. You cannot overcharge the pack that way if everything works fine. The HVC is only a safety
measure if something goes wrong with the charging sources, so no warning level is needed.
Regarding LVC I have configured my battery
monitors to start beeping when reaching 20 % SoC, so I have plenty of time to react before things go whacky.